【０００１】
【産業上の利用分野】
本発明は縦置き機関を車体前部の低位置へ搭載するのに有利な車両の前輪駆動機構に関するものである。
【０００２】
【従来の技術】
従来の車両の前輪駆動機構では、機関の回転を左右の前輪の駆動軸へ伝達するために、入力軸や終減速機を車幅中心部に配設している。
【０００３】
しかし、上述の配置では、特に縦置き機関の場合に、機関と終減速機との干渉を避けるために、車枠周辺の構造物を全般的に上方へ移動しなければならず、車高が必要以上に高くなつてしまうという問題がある。また、左右の前輪の車軸と駆動軸とを連結する自在継手を、各前輪のナツクルを操向可能に支持するキングピンの軸線と交差するように配置する都合から、自在継手の許容交差角（軸と軸との屈曲角）が制限され、一般車両と同等の前輪舵角を得ることが難しく、車両の小回り性が低下するという問題がある。
【０００４】
上述の問題を解決するために、本出願人は特願平６−２７２５１ 号により、左右の前輪の車軸と駆動軸とを、キングピンの軸線と交差して配設される１対の自在継手により連結し、さらに左右１対の駆動軸を車幅中心で第３の自在継手により互いに連結し、左右１対の駆動軸が車幅中心に向つて下方へ傾斜するＶ型配置にすることにより、車高が低く、一般車両と同等の小回り性を確保できるようにした車両の前輪駆動機構を提案している。
【０００５】
例えば特開昭５８−１２６２２２ 号公報などに開示されるように、左右１対の駆動軸が車幅中心に向つて下方だけでなく前方へも傾斜する三次元Ｖ型配置にすれば、さらに車高を低く前輪舵角を大きくできるが、駆動軸系の強度上に問題が生じる。つまり、左右１対の駆動軸を車軸よりも前下方かつ車幅中心に配設した自在継手により連結する三次元Ｖ型配置では、通常のバンジヨー型の車軸ケースに装着されるものと同じ構造の終減速機を接続しようすると、車軸ケースの形状が第３の自在継手の前方偏倚量分だけえぐられた格好になり、ばね上荷重に対する車軸ケースの強度が不足する。つまり、車軸ケースには前輪のばね上荷重に基づく単純な上下方向の曲げ荷重と、路面からの前後方向の入力に基づく前後方向の曲げ荷重とが作用することになり、車軸ケースの剛性強度を確保するには、車軸ケースの肉厚を厚くするなどの対策が必要になり、大幅な重量増加を来たすという問題がある。
【０００６】
【発明が解決しようとする課題】
本発明の目的は上述の問題に鑑み、左右１対の駆動軸を三次元Ｖ型配置に支持する車軸ケースが、上下・前後方向の曲げ荷重や捩り荷重に耐え得るようにした、車両の前輪駆動機構を提供することにある。
【０００７】
【課題を解決するための手段】
上記目的を達成するために、本発明の構成は左右の前輪の車軸に自在継手により駆動軸を連結し、車軸よりも下方かつ前方に偏倚して車幅中心に配設した自在継手により左右１対の駆動軸を互いに連結し、一方の駆動軸の中間部分を分割しかつ機関の回転を前輪へ伝達する終減速機に接続し、１対の駆動軸を支持する車軸ケースに後方へ水平に延びる棚状の補強板を一体的に設けたものである。
【０００８】
【作用】
終減速機が比較的低い位置に配設される場合に、終減速機の接続部と補強板との干渉を避けるために、終減速機の下側に補強板を配設するとなれば、補強板の下面と路面との間隔が非常に狭くなり、車両が凹凸のある路面を走行する際に、補強板が路面と干渉する恐れがある。
【０００９】
本発明では、左右の駆動軸が車幅中心で車軸よりも下方かつ前方へ偏倚した自在継手により互いに連結される。これにより、舵角を大きく、機関や終減速機の搭載位置を低くできる。車軸ケースに対する終減速機の配置を、車両の鉛直面よりも若干後方かつ斜め上方へ傾斜させる。これにより、車軸ケースの終減速機との接続部の最低地上高に余裕ができ、終減速機の下面と車軸ケースの下面に水平な補強板を配設することができる。
【００１０】
前輪のばね上荷重が車軸ケースに及ぼす曲げ荷重に対し、車軸ケースは補強板により補強される。
【００１１】
【実施例】
図１は本発明に係る車両の前輪駆動機構の概略構成を示す背面図、図２は同前輪駆動機構を示す背面図、図３は同平面図、図４は終減速機の側面図、図５は車軸ケースの側面断面図である。本発明は縦置き機関前置・後輪駆動車両を全輪駆動車両に構成する場合に、車枠１８に対する機関２４の搭載位置を変更しないかできるだけ低くして、機関２４の回転を主変速機と終減速機（差動装置）２１を経て左右の前輪２へ伝達するものである。左右の前輪２を結合する車軸４は、自在継手（等速自在継手）９により左右の駆動軸１０，２０に連結され、駆動軸１０，２０は車幅中心で自在継手２３により互いに連結される。実際には、駆動軸１０は一直線に並ぶ左半の駆動軸１０と右半の駆動軸１０Ａとに分割され、各駆動軸１０，１０Ａは車幅中心から偏倚して配設した終減速機２１の各側部傘歯車に結合される。
【００１２】
図３に示すように、終減速機２１は前後方向の入力軸３５の回転を、駆動軸１０，１０Ａを中心とするケージ３２の回転に変換するものであり、入力軸３５に結合した傘歯車３４をケージ３２に結合したクラウン歯車３１に噛み合せ、ケージ３２の内部に駆動軸１０，１０Ａと直交する軸により支持した中間傘歯車を、左右１対の側部傘歯車に噛み合せてなる。しかし、終減速機２１の構成は公知であるから、これ以上説明しない。
【００１３】
図２，５に示すように、機関２４の下部で横方向に延びる車軸ケース１６は、断面筒状のものであるが、下壁に後述する補強のための補強板１６ｂが一体的に構成され、さらに終減速機２１を収容するケースが一体的に構成される。車軸ケース１６は左右両端部にＣ字形の腕１４を一体に構成され、公知の上下に２分割されたキングピン１３によりナツクル１２を揺動可能に支持される。ナツクル１２はＣ字形の腕と水平な円筒部１２ａを一体に備えている。
【００１４】
図３に示すように、車軸ケース１６は左右１対のほぼ長方形をなす水平な平坦面１６ａを備えられ、各平坦面１６ａの上に懸架用板ばね１９を重ね合せ、板ばね１９を抱持する公知の前後１対のＵボルトの下端を、ボルト挿通孔２６，２７へ挿通し、かつナツトにより締結するようになつている。板ばね１９の前後端部は車枠１８（図１）に横方向のピンにより支持される。車軸ケース１６の内部で左右１対の駆動軸１０，２０は、図２に示すように車幅中心へ向けて下方へ傾斜され、さらに、図３に示すように左右の車軸４よりも傾め前方へ突出され、自在継手２３により互いに連結される。車軸４はナツクル１２の円筒部１２ａを貫通し、車軸４の外端フランジを円筒部１２ａに回転支持した前輪２に結合される。上述のように、左右１対の駆動軸１０，２０は車幅中心へ向つて斜め下方へ傾斜し、かつ斜め前方へ張り出しているので、駆動軸１０，２０の向きにならつて車軸ケース１６も湾曲される。
【００１５】
本発明では車軸ケース１６の剛性強度を高めるために、車軸ケース１６の下縁部に後方へほぼ水平に突出する棚状の補強板１６ｂを一体に構成される。図２，３には補強板１６ｂを明確にするために、補強板１６ｂの上面と後面に格子状の模様を付した。入力軸３５は駆動軸１０と垂直かつ後方へ水平に延び、平面的にみて車幅中心線ｙに対し傾斜する。
【００１６】
図５に示すように、車軸ケース１６の中間部分は円筒状をなし、かつ下壁から後方へ突出するほぼ水平な補強板１６ｂを一体に形成される。図３に示すように、補強板１６ｂの後縁は左右の車軸４よりも後方へ突出している。
【００１７】
機関２４の回転は図示してない主変速機、入力軸３５、終減速機２１を経て各駆動軸１０，１０Ａへ伝達され、駆動軸１０の回転は自在継手９、車軸４を経て左前輪２へ伝達される。駆動軸１０Ａの回転は自在継手２３、駆動軸２０、自在継手９、車軸４を経て右前輪２へ伝達される。
【００１８】
図６に示す部分変更実施例では、車軸ケース１６の終減速機２１の部分で、終減速機２１の下壁から後方へ水平な補強板１６ｂが突出されるのに対し、終減速機２１のケース３３は後上がりに傾斜され、入力軸３５は後方かつ斜め上方へ突出される。終減速機２１の取付角度を後方かつ斜め上方へせり上げることにより、補強板１６ｂの地上高ｂを、図４に示す実施例における補強板１６ｂの地上高ａよりも高くでき、また終減速機２１の入力軸３５の後端が高くなり、前輪操舵用タイロツド３７の配置に余裕ができる。
【００１９】
【発明の効果】
本発明は上述のように、左右１対の駆動軸が車幅中心へ向けて斜め下方へ傾斜し、かつ斜め前方へ張り出しているので、縦置き機関を車枠の低位置に搭載でき、車体重心を低くできる。
【００２０】
車軸ケースの下壁部に後方へ張出す水平な補強板を設けたので、車軸ケースの重量増加を抑えつつ車軸ケースの曲げ剛性を高めることができる。
【００２１】
左右１対の駆動軸が車幅中心で自在継手により連結されるから、各自在継手における軸相互の交差角が非常に小さく（一直線に近く）、自在継手に無理がなく耐久性に優れる。
【００２２】
終減速機を車幅中心から片側へ偏倚して配設したことにより、機関との干渉を回避できる。
【００２３】
終減速機の取付角度を後方かつ斜め上方へせり上げることにより、補強板の地上高を高くでき、また終減速機の入力軸の後端が高くなり、前輪操舵用タイロツドの配置に余裕ができる。
【図面の簡単な説明】
【図１】本発明に係る車両の前輪駆動機構の概略構成を示す背面図である。
【図２】同前輪駆動機構を示す背面図である。
【図３】同前輪駆動機構の平面図である。
【図４】終減速機の配置を示す側面図である。
【図５】車軸ケースの中間部分の側面断面図である。
【図６】本発明の部分的変更実施例に係る終減速機の配置を示す側面図である。
【符号の説明】
２：前輪 ４：車軸 ９：自在継手 １０，１０Ａ，２０：駆動軸 １２：ナツクル １２ａ：円筒部 １３：キングピン １４：腕 １６：車軸ケース １６ｂ：補強板 １８：車枠 １９：板ばね ２１：終減速機 ２３：自在継手 ２４：内燃機関 ２６，２７：ボルト挿通孔 ３２：ケージ ３５：入力軸[0001]
[Industrial applications]
TECHNICAL FIELD The present invention relates to a front wheel drive mechanism of a vehicle which is advantageous for mounting a vertical engine at a low position at a front portion of a vehicle body.
[0002]
[Prior art]
In a conventional front wheel drive mechanism of a vehicle, an input shaft and a final reduction gear are disposed at a center portion of a vehicle width in order to transmit rotation of an engine to drive shafts of left and right front wheels.
[0003]
However, in the above arrangement, especially in the case of a vertical engine, the structure around the vehicle frame must be generally moved upward in order to avoid interference between the engine and the final reduction gear. There is a problem that it becomes higher than above. Also, since the universal joint connecting the axles of the left and right front wheels and the drive shaft is arranged to intersect with the axis of the kingpin for supporting the knuckle of each front wheel so as to be steerable, the allowable crossing angle (shaft) of the universal joint is determined. Angle between the shaft and the shaft) is limited, and it is difficult to obtain a front wheel steering angle equivalent to that of a general vehicle, and there is a problem that the small turning property of the vehicle is reduced.
[0004]
In order to solve the above-mentioned problem, the applicant of the present invention disclosed in Japanese Patent Application No. 6-27251 that the axles and the drive shafts of the left and right front wheels are connected by a pair of universal joints arranged to intersect the axis of the kingpin. And a pair of left and right drive shafts are connected to each other by a third universal joint at the center of the vehicle width to form a V-shaped arrangement in which the pair of left and right drive shafts is inclined downward toward the center of the vehicle width. A front wheel drive mechanism for a vehicle that has a low vehicle height and is capable of ensuring the same small turning performance as a general vehicle has been proposed.
[0005]
For example, as disclosed in Japanese Patent Application Laid-Open No. 58-126222, a three-dimensional V-shaped arrangement in which a pair of left and right drive shafts are inclined not only downward but also forward toward the center of the vehicle width will further enhance the vehicle. Although the height can be lowered and the front wheel steering angle can be increased, a problem occurs in the strength of the drive shaft system. In other words, in a three-dimensional V-type arrangement in which a pair of left and right drive shafts are connected by a universal joint disposed below the axle and at the center of the vehicle width, the three-dimensional V-type arrangement has the same structure as that mounted on a normal banjo-yo type axle case. When the final reduction gear is connected, the shape of the axle case is cut off by the amount of forward bias of the third universal joint, and the strength of the axle case against a sprung load is insufficient. In other words, a simple vertical bending load based on the sprung load of the front wheel and a longitudinal bending load based on the longitudinal input from the road surface act on the axle case, and the rigidity of the axle case is reduced. To ensure this, it is necessary to take measures such as increasing the thickness of the axle case, and there is a problem that the weight increases significantly.
[0006]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a front wheel of a vehicle in which an axle case supporting a pair of left and right drive shafts in a three-dimensional V-shape arrangement can withstand bending loads and torsional loads in vertical and forward and backward directions. It is to provide a drive mechanism.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is configured such that a drive shaft is connected to the axles of the left and right front wheels by a universal joint, and the left and right sides are deflected downward and forward from the axle and disposed at the center of the vehicle width. A pair of drive shafts are connected to each other, an intermediate portion of one drive shaft is divided and connected to a final reduction gear that transmits the rotation of the engine to the front wheels, and is horizontally rearwardly mounted on an axle case supporting the pair of drive shafts. An extended shelf-shaped reinforcing plate is integrally provided.
[0008]
[Action]
If the final reduction gear is located at a relatively low position, if reinforcement plates are to be provided below the final reduction gear to avoid interference between the connection of the final reduction gear and the reinforcement plate, reinforcement The distance between the lower surface of the plate and the road surface becomes very narrow, and when the vehicle travels on an uneven road surface, the reinforcing plate may interfere with the road surface.
[0009]
In the present invention, the left and right drive shafts are connected to each other by a universal joint that is biased forward and downward from the axle at the center of the vehicle width. This makes it possible to increase the steering angle and lower the mounting position of the engine and the final reduction gear. The position of the final reduction gear with respect to the axle case is inclined slightly backward and obliquely upward from the vertical plane of the vehicle. As a result, the minimum ground clearance at the connection portion of the axle case with the final reduction gear can be provided, and a horizontal reinforcing plate can be disposed on the lower surface of the final reduction gear and the lower surface of the axle case.
[0010]
The axle case is reinforced by the reinforcing plate against the bending load applied to the axle case by the sprung load of the front wheel.
[0011]
【Example】
FIG. 1 is a rear view showing a schematic configuration of a front wheel drive mechanism of a vehicle according to the present invention, FIG. 2 is a rear view showing the front wheel drive mechanism, FIG. 3 is a plan view of the same, FIG. 5 is a side sectional view of the axle case. In the present invention, when the vertical engine front / rear wheel drive vehicle is configured as an all-wheel drive vehicle, the mounting position of the engine 24 with respect to the vehicle frame 18 is not changed or made as low as possible, and the rotation of the engine 24 is set to the main transmission. This is transmitted to the left and right front wheels 2 via a final reduction gear (differential device) 21. The axle 4 connecting the left and right front wheels 2 is connected to left and right drive shafts 10 and 20 by a universal joint (constant velocity universal joint) 9, and the drive shafts 10 and 20 are connected to each other by a universal joint 23 at the center of the vehicle width. . In practice, the drive shaft 10 is divided into a left half drive shaft 10 and a right half drive shaft 10A which are aligned, and each of the drive shafts 10 and 10A is disposed so as to be offset from the center of the vehicle width. Of each side bevel gear.
[0012]
As shown in FIG. 3, the final reduction gear 21 converts the rotation of the input shaft 35 in the front-rear direction into the rotation of the cage 32 about the drive shafts 10 and 10A, and the bevel gear coupled to the input shaft 35. 34 is meshed with a crown gear 31 connected to a cage 32, and an intermediate bevel gear supported inside the cage 32 by a shaft orthogonal to the drive shafts 10 and 10A is meshed with a pair of left and right side bevel gears. However, since the configuration of the final reduction gear 21 is known, it will not be described further.
[0013]
As shown in FIGS. 2 and 5, the axle case 16 extending laterally below the engine 24 has a cylindrical cross-section, but a reinforcing plate 16b for later-described reinforcement is integrally formed on the lower wall. Further, a case accommodating the final reduction gear 21 is integrally formed. The axle case 16 has a C-shaped arm 14 integrally formed at both left and right end portions, and the knuckle 12 is swingably supported by a known king pin 13 divided into upper and lower parts. The knuckle 12 integrally has a C-shaped arm and a horizontal cylindrical portion 12a.
[0014]
As shown in FIG. 3, the axle case 16 is provided with a pair of left and right, substantially rectangular, horizontal flat surfaces 16a, a suspension leaf spring 19 is superimposed on each flat surface 16a, and the leaf spring 19 is held. The lower ends of a pair of known front and rear U bolts are inserted into the bolt insertion holes 26 and 27 and fastened by nuts. The front and rear ends of the leaf spring 19 are supported on the vehicle frame 18 (FIG. 1) by lateral pins. Inside the axle case 16, a pair of left and right drive shafts 10 and 20 are inclined downward toward the center of the vehicle width as shown in FIG. 2, and further inclined than the left and right axles 4 as shown in FIG. It projects forward and is connected to each other by a universal joint 23. The axle 4 penetrates the cylindrical portion 12a of the knuckle 12, and is connected to the front wheel 2 which has the outer end flange of the axle 4 rotatably supported by the cylindrical portion 12a. As described above, the pair of left and right drive shafts 10 and 20 is inclined obliquely downward toward the center of the vehicle width and projects obliquely forward, so that the axle case 16 follows the direction of the drive shafts 10 and 20. Curved.
[0015]
In the present invention, in order to increase the rigidity of the axle case 16, a shelf-like reinforcing plate 16b is formed integrally with the lower edge of the axle case 16 and projects substantially horizontally rearward. 2 and 3, a lattice-like pattern is provided on the upper surface and the rear surface of the reinforcing plate 16b in order to clarify the reinforcing plate 16b. The input shaft 35 extends vertically perpendicular to the drive shaft 10 and horizontally rearward, and is inclined with respect to the vehicle width center line y in plan view.
[0016]
As shown in FIG. 5, an intermediate portion of the axle case 16 has a cylindrical shape, and is formed integrally with a substantially horizontal reinforcing plate 16b projecting rearward from a lower wall. As shown in FIG. 3, the rear edge of the reinforcing plate 16b projects rearward from the left and right axles 4.
[0017]
The rotation of the engine 24 is transmitted to the respective drive shafts 10 and 10A via a main transmission, an input shaft 35, and a final reduction gear 21 (not shown), and the rotation of the drive shaft 10 is transmitted via the universal joint 9 and the axle 4 to the left front wheel 2. Is transmitted to The rotation of the drive shaft 10A is transmitted to the right front wheel 2 via the universal joint 23, the drive shaft 20, the universal joint 9, and the axle 4.
[0018]
In the partially modified embodiment shown in FIG. 6, the horizontal reinforcing plate 16 b projects rearward from the lower wall of the final reduction gear 21 at the final reduction gear 21 of the axle case 16. The case 33 is inclined rearward and upward, and the input shaft 35 projects rearward and obliquely upward. By raising the mounting angle of the final reduction gear 21 rearward and obliquely upward, the ground height b of the reinforcing plate 16b can be made higher than the ground height a of the reinforcing plate 16b in the embodiment shown in FIG. The rear end of the input shaft 35 of the input shaft 21 is raised, so that the tie rods 37 for steering the front wheels can be arranged with a margin.
[0019]
【The invention's effect】
As described above, in the present invention, a pair of left and right drive shafts are inclined obliquely downward toward the center of the vehicle width and project obliquely forward, so that the vertical engine can be mounted at a low position of the vehicle frame, and Can be lowered.
[0020]
Since the horizontal reinforcing plate extending rearward is provided on the lower wall of the axle case, the bending rigidity of the axle case can be increased while suppressing an increase in the weight of the axle case.
[0021]
Since a pair of left and right drive shafts are connected by a universal joint at the center of the vehicle width, the crossing angle between the shafts in each universal joint is very small (close to a straight line), and the universal joint is comfortable and has excellent durability.
[0022]
By disposing the final reduction gear so as to be deviated to one side from the center of the vehicle width, interference with the engine can be avoided.
[0023]
By raising the mounting angle of the final reduction gear backward and diagonally upward, the height of the reinforcement plate above the ground can be increased, and the rear end of the input shaft of the final reduction gear can be increased, so that the tie rods for front wheel steering can be arranged more freely. .
[Brief description of the drawings]
FIG. 1 is a rear view showing a schematic configuration of a front wheel drive mechanism of a vehicle according to the present invention.
FIG. 2 is a rear view showing the front wheel drive mechanism.
FIG. 3 is a plan view of the front wheel drive mechanism.
FIG. 4 is a side view showing an arrangement of a final reduction gear.
FIG. 5 is a side sectional view of an intermediate portion of the axle case.
FIG. 6 is a side view showing an arrangement of a final reduction gear according to a partially modified embodiment of the present invention.
[Explanation of symbols]
2: Front wheel 4: Axle 9: Universal joint 10, 10A, 20: Drive shaft 12: Knuckle 12a: Cylindrical part 13: King pin 14: Arm 16: Axle case 16b: Reinforcement plate 18: Car frame 19: Leaf spring 21: Final deceleration Machine 23: universal joint 24: internal combustion engine 26, 27: bolt insertion hole 32: cage 35: input shaft
